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""" | |
Taken from ESPNet | |
""" | |
import torch | |
from torch.functional import stft as torch_stft | |
from torch_complex.tensor import ComplexTensor | |
from Utility.utils import make_pad_mask | |
class STFT(torch.nn.Module): | |
def __init__(self, n_fft=512, win_length=None, hop_length=128, window="hann", center=True, normalized=False, | |
onesided=True): | |
super().__init__() | |
self.n_fft = n_fft | |
if win_length is None: | |
self.win_length = n_fft | |
else: | |
self.win_length = win_length | |
self.hop_length = hop_length | |
self.center = center | |
self.normalized = normalized | |
self.onesided = onesided | |
self.window = window | |
def extra_repr(self): | |
return (f"n_fft={self.n_fft}, " | |
f"win_length={self.win_length}, " | |
f"hop_length={self.hop_length}, " | |
f"center={self.center}, " | |
f"normalized={self.normalized}, " | |
f"onesided={self.onesided}") | |
def forward(self, input_wave, ilens=None): | |
""" | |
STFT forward function. | |
Args: | |
input_wave: (Batch, Nsamples) or (Batch, Nsample, Channels) | |
ilens: (Batch) | |
Returns: | |
output: (Batch, Frames, Freq, 2) or (Batch, Frames, Channels, Freq, 2) | |
""" | |
bs = input_wave.size(0) | |
if input_wave.dim() == 3: | |
multi_channel = True | |
# input: (Batch, Nsample, Channels) -> (Batch * Channels, Nsample) | |
input_wave = input_wave.transpose(1, 2).reshape(-1, input_wave.size(1)) | |
else: | |
multi_channel = False | |
# output: (Batch, Freq, Frames, 2=real_imag) | |
# or (Batch, Channel, Freq, Frames, 2=real_imag) | |
if self.window is not None: | |
window_func = getattr(torch, f"{self.window}_window") | |
window = window_func(self.win_length, dtype=input_wave.dtype, device=input_wave.device) | |
else: | |
window = None | |
complex_output = torch_stft(input=input_wave, | |
n_fft=self.n_fft, | |
win_length=self.win_length, | |
hop_length=self.hop_length, | |
center=self.center, | |
window=window, | |
normalized=self.normalized, | |
onesided=self.onesided, | |
return_complex=True) | |
output = torch.view_as_real(complex_output) | |
# output: (Batch, Freq, Frames, 2=real_imag) | |
# -> (Batch, Frames, Freq, 2=real_imag) | |
output = output.transpose(1, 2) | |
if multi_channel: | |
# output: (Batch * Channel, Frames, Freq, 2=real_imag) | |
# -> (Batch, Frame, Channel, Freq, 2=real_imag) | |
output = output.view(bs, -1, output.size(1), output.size(2), 2).transpose(1, 2) | |
if ilens is not None: | |
if self.center: | |
pad = self.win_length // 2 | |
ilens = ilens + 2 * pad | |
olens = (ilens - self.win_length) // self.hop_length + 1 | |
output.masked_fill_(make_pad_mask(olens, output, 1), 0.0) | |
else: | |
olens = None | |
return output, olens | |
def inverse(self, input, ilens=None): | |
""" | |
Inverse STFT. | |
Args: | |
input: Tensor(batch, T, F, 2) or ComplexTensor(batch, T, F) | |
ilens: (batch,) | |
Returns: | |
wavs: (batch, samples) | |
ilens: (batch,) | |
""" | |
istft = torch.functional.istft | |
if self.window is not None: | |
window_func = getattr(torch, f"{self.window}_window") | |
window = window_func(self.win_length, dtype=input.dtype, device=input.device) | |
else: | |
window = None | |
if isinstance(input, ComplexTensor): | |
input = torch.stack([input.real, input.imag], dim=-1) | |
assert input.shape[-1] == 2 | |
input = input.transpose(1, 2) | |
wavs = istft(input, n_fft=self.n_fft, hop_length=self.hop_length, win_length=self.win_length, window=window, center=self.center, | |
normalized=self.normalized, onesided=self.onesided, length=ilens.max() if ilens is not None else ilens) | |
return wavs, ilens | |